Wind turbine generators for generating electric power using wind power, which is a natural form of energy, are known. Such a wind turbine generator includes a nacelle disposed on a tower. The nacelle includes a rotor head equipped with blades, a main shaft connected to the rotor head so as to integrally rotate with the rotor head, a gearbox connected to the main shaft that rotates upon receiving the wind power supplied to the blades, and a generator driven by a shaft output from the gearbox. According to the wind turbine generator having this structure, the rotor head is equipped with the blades which convert wind power into a rotational force, and the main shaft rotates to generate a shaft output. The rotational speed is increased via the gearbox connected to the main shaft and the resulting shaft output is transmitted to the generator. Consequently, the shaft output obtained by converting the wind power into the rotational force is used as a driving source of the generator, and thus power generation can be performed using the wind power as motive power for the generator.
Since recent wind turbine generators tend to increase their output by increasing the size thereof, the sizes of components such as the rotor head, the main shaft, the gearbox, and the generator also increase, resulting in an increase in weight, and an increase in the need to assure alignment between the gearbox shaft and the generator main shaft. Misalignment can lead to premature and costly failures of the system, as well as loss in income due to the inability to generate energy.
Accordingly, as market pressures continue to demand wind turbine systems that provide lower cost, greater reliability, and longer service lives, challenges remain and a need persists for improvements in methods and apparatuses for use in the maintenance of wind turbine systems.